The present application relates generally to the field of terrain avoidance systems. More specifically, the application relates to a terrain avoidance system that may suppress false alerts.
Terrain awareness systems, such as Terrain Awareness Warning Systems (TAWS), typically provide flight crews with information (e.g., alerts, warnings, displays of terrain data, etc.) related to detection of potentially hazardous terrain situations that pose or may pose a threat to the continued safe flight and landing of an aircraft and provide warnings or alerts in sufficient time for the flight crew to take effective action to prevent a controlled flight into terrain (CFIT). Terrain awareness systems generally have three alerting functions including a Ground Proximity Warning System (GPWS) alerting function, a Forward Looking Terrain Avoidance (FLTA) alerting function, and a Premature Descent Alerting (PDA) function.
Terrain awareness systems have been implemented using terrain elevation databases to support the FLTA alerting function. These systems look ahead of the aircraft's current position by using a terrain elevation database to determine if there is terrain in regions that would be potentially hazardous to the aircraft.
While not required by the Federal Aviation Administration (FAA) TAWS technical standard order, alerting for obstacles (e.g., man-made structures such as towers or buildings) that pose a hazard to the aircraft is often included in TAWS packages. Current TAWS packages tend to solely use obstacle databases to support this additional obstacle alerting function.
An alternative means of compliance with the FAA TAWS forward looking terrain alerting function requirements (which are currently defined in FAA Technical Standard Order (TSO) C115b) is a Radar-based TAWS (R-TAWS). Such a system uses airborne radar sensors (e.g., similar to the radar that is used for weather and windshear detection) to detect terrain and/or obstacles that are potentially hazardous to the aircraft rather than or in addition to using a database. However, this alternative method of detection that uses radar to detect terrain and/or obstacles in regions that may be hazardous to the aircraft may have difficulty achieving an acceptably low false detection rate.
What is needed is a method for reducing the false alert rate for the detection of hazardous terrain and/or obstacles in an R-TAWS. What is also needed is an improved R-TAWS that has a reduced rate of false alerts of terrain and/or obstacles.